ABSTRACT

Twin-line (two seed lines 7.25 in apart per bed) and conventional single seed line per bed cotton production systems were compared at 19 sites across Arizona in 2002 and data analysis was completed in 11 of the experiments. The twin-line system produced more lint than the conventional single-line system at 3 of 11 locations; the yields of the twin-line and single-line systems were 1273 and 1186 lb/acre, 1572 and 1461 lb/acre, and 1309 and 1210 lb/acre, respectively, at the Grasty, Ramona, and Wells sites, respectively. There were no significant differences in yield or fiber micronaire in 5 of the 11 experiments. The twin-line system produced less lint than the conventional system at 3 of 11 locations; yields of the twin-line and single-line systems were 1400 and 1489 lb/acre, 1065 and 1200 lb/acre, and 1271 and 1431 lb/acre, respectively, at the Cooley, Papago, and Wakimoto sites, respectively. Fiber micronaire was reduced in two experiments; the micronaire values were 4.46 and 4.78, and 4.60 and 4.85 in the twin-line and single-line systems, respectively, at the Papago and Grasty sites, respectively. Research will continue in 2003 in order to develop system comparison data for multiple years and to elucidate the reasons for the variable results measured in the 2002 cotton season.